diff --git a/core/mem/virtual/virtual_darwin.odin b/core/mem/virtual/virtual_darwin.odin
new file mode 100644
index 000000000..0635c83d4
--- /dev/null
+++ b/core/mem/virtual/virtual_darwin.odin
@@ -0,0 +1,20 @@
+package mem_virtual
+
+import "core:sys/posix"
+
+_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
+	result := posix.mmap(nil, size, {}, {.ANONYMOUS, .PRIVATE})
+	if result == posix.MAP_FAILED {
+		assert_contextless(posix.errno() == .ENOMEM)
+		return nil, .Out_Of_Memory
+	}
+
+	return ([^]byte)(uintptr(result))[:size], nil
+}
+
+_decommit :: proc "contextless" (data: rawptr, size: uint) {
+	MADV_FREE :: 5
+
+	posix.mprotect(data, size, {})
+	posix.posix_madvise(data, size, transmute(posix.MAdvice)i32(MADV_FREE))
+}
diff --git a/core/mem/virtual/virtual_freebsd.odin b/core/mem/virtual/virtual_freebsd.odin
new file mode 100644
index 000000000..af0f31733
--- /dev/null
+++ b/core/mem/virtual/virtual_freebsd.odin
@@ -0,0 +1,26 @@
+package mem_virtual
+
+import "core:sys/posix"
+
+_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
+
+	PROT_MAX :: proc "contextless" (flags: posix.Prot_Flags) -> posix.Prot_Flags {
+		_PROT_MAX_SHIFT :: 16
+		return transmute(posix.Prot_Flags)(transmute(i32)flags << _PROT_MAX_SHIFT)
+	}
+
+	result := posix.mmap(nil, size, PROT_MAX({.READ, .WRITE, .EXEC}), {.ANONYMOUS, .PRIVATE})
+	if result == posix.MAP_FAILED {
+		assert_contextless(posix.errno() == .ENOMEM)
+		return nil, .Out_Of_Memory
+	}
+
+	return ([^]byte)(uintptr(result))[:size], nil
+}
+
+_decommit :: proc "contextless" (data: rawptr, size: uint) {
+	MADV_FREE :: 5
+
+	posix.mprotect(data, size, {})
+	posix.posix_madvise(data, size, transmute(posix.MAdvice)i32(MADV_FREE))
+}
diff --git a/core/mem/virtual/virtual_netbsd.odin b/core/mem/virtual/virtual_netbsd.odin
new file mode 100644
index 000000000..588625cc7
--- /dev/null
+++ b/core/mem/virtual/virtual_netbsd.odin
@@ -0,0 +1,25 @@
+package mem_virtual
+
+import "core:sys/posix"
+
+_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
+
+	PROT_MPROTECT :: proc "contextless" (flags: posix.Prot_Flags) -> posix.Prot_Flags {
+		return transmute(posix.Prot_Flags)(transmute(i32)flags << 3)
+	}
+
+	result := posix.mmap(nil, size, PROT_MPROTECT({.READ, .WRITE, .EXEC}), {.ANONYMOUS, .PRIVATE})
+	if result == posix.MAP_FAILED {
+		assert_contextless(posix.errno() == .ENOMEM)
+		return nil, .Out_Of_Memory
+	}
+
+	return ([^]byte)(uintptr(result))[:size], nil
+}
+
+_decommit :: proc "contextless" (data: rawptr, size: uint) {
+	MADV_FREE :: 6
+
+	posix.mprotect(data, size, {})
+	posix.posix_madvise(data, size, transmute(posix.MAdvice)i32(MADV_FREE))
+}
diff --git a/core/mem/virtual/virtual_openbsd.odin b/core/mem/virtual/virtual_openbsd.odin
new file mode 100644
index 000000000..83f7ca9ca
--- /dev/null
+++ b/core/mem/virtual/virtual_openbsd.odin
@@ -0,0 +1,20 @@
+package mem_virtual
+
+import "core:sys/posix"
+
+_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
+	result := posix.mmap(nil, size, {}, {.ANONYMOUS, .PRIVATE})
+	if result == posix.MAP_FAILED {
+		assert_contextless(posix.errno() == .ENOMEM)
+		return nil, .Out_Of_Memory
+	}
+
+	return ([^]byte)(uintptr(result))[:size], nil
+}
+
+_decommit :: proc "contextless" (data: rawptr, size: uint) {
+	MADV_FREE :: 6
+
+	posix.mprotect(data, size, {})
+	posix.posix_madvise(data, size, transmute(posix.MAdvice)i32(MADV_FREE))
+}
diff --git a/core/mem/virtual/virtual_platform.odin b/core/mem/virtual/virtual_platform.odin
index 54c42ce4b..31e9cfca8 100644
--- a/core/mem/virtual/virtual_platform.odin
+++ b/core/mem/virtual/virtual_platform.odin
@@ -15,7 +15,9 @@ platform_memory_alloc :: proc "contextless" (to_commit, to_reserve: uint) -> (bl
 	to_commit = clamp(to_commit, size_of(Platform_Memory_Block), total_to_reserved)
 	
 	data := reserve(total_to_reserved) or_return
-	commit(raw_data(data), to_commit)
+
+	commit_err := commit(raw_data(data), to_commit)
+	assert_contextless(commit_err == nil)
 	
 	block = (^Platform_Memory_Block)(raw_data(data))
 	block.committed = to_commit
diff --git a/core/mem/virtual/virtual_posix.odin b/core/mem/virtual/virtual_posix.odin
index c3d6a9095..0b304a5e7 100644
--- a/core/mem/virtual/virtual_posix.odin
+++ b/core/mem/virtual/virtual_posix.odin
@@ -4,36 +4,18 @@ package mem_virtual
 
 import "core:sys/posix"
 
-// Define non-posix needed flags:
-when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD {
-	MADV_FREE :: 5      /* pages unneeded, discard contents */
-} else when ODIN_OS == .OpenBSD || ODIN_OS == .NetBSD {
-	MADV_FREE :: 6
-}
-
-_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
-	flags  := posix.Map_Flags{ .ANONYMOUS, .PRIVATE }
-	result := posix.mmap(nil, size, {}, flags)
-	if result == posix.MAP_FAILED {
-		return nil, .Out_Of_Memory
-	}
-
-	return ([^]byte)(uintptr(result))[:size], nil
-}
-
 _commit :: proc "contextless" (data: rawptr, size: uint) -> Allocator_Error {
 	if posix.mprotect(data, size, { .READ, .WRITE }) != .OK {
-		return .Out_Of_Memory
+		#partial switch posix.errno() {
+		case .EACCES, .EPERM:   return .Invalid_Pointer
+		case .ENOTSUP, .EINVAL: return .Invalid_Argument
+		case:                   return .Out_Of_Memory
+		}
 	}
 
 	return nil
 }
 
-_decommit :: proc "contextless" (data: rawptr, size: uint) {
-	posix.mprotect(data, size, {})
-	posix.posix_madvise(data, size, transmute(posix.MAdvice)i32(MADV_FREE))
-}
-
 _release :: proc "contextless" (data: rawptr, size: uint) {
 	posix.munmap(data, size)
 }